In data storage, storage device mirroring replicates data stored on a first data storage device to a second data storage device, in order to ensure redundancy. For a storage system comprising a pair of storage devices, mirroring can be implemented either synchronously or asynchronously. During synchronous mirroring, a host communicating with the storage system receives a write acknowledgement after data is successfully written to both of the mirrored storage devices. During asynchronous mirroring, the host receives the write acknowledgement after the data is written to a first of the mirrored storage devices, and the data is written to a second of the mirrored storage devices at a later time.
The description above is presented as a general overview of related art in this field and should not be construed as an admission that any of the information it contains constitutes prior art against the present patent application.